Image Spam On The Rise
Reports, and my own experience, indicate that the percentage of image spam hitting inboxes has dramatically increased over the last few months. With this type of spam, the information that the spammer wants you to see is rendered as an image. Because many spam filtering systems cannot easily "read" words within images, image based spam is more likely to get through to your inbox.
Although a lot of image spam is of the stock scam variety, I am now seeing image spam for all kinds of products including the almost ubiquitous Viagra adds. Image based spam is not new, but its apparent "success" means that more and more spammers have now embraced the practise. Some experts claim that image spam may now account for up to 30 percent of all spam. Spammers have also honed their technique so that the new breed of image spam is even more likely to bypass filters than its predecessors. Small, random changes are made to the images for each message sent. The actual size of the image may also be randomized. Although a human may not even notice these minor changes, they can effectively make the image unique as far as a spam filtering system is concerned. The background of the image may contain random squiggles or dots that make it difficult for even sophisticated character recognition software to extract key words. Thus, the spam is able to sneak past.
The spam messages often also include random words or phrases in plain-text along with the images. This random text has no relation to the spam message itself and is designed to further confuse spam filters.
The good news is that anti-spam experts are working on improving spam-filtering procedures to battle this new scourge. In the mean time, there is always the trusty old "Delete" key.
Last updated: 6th December 2006
First published: 6th December 2006
Write-up by Brett M.Christensen